New sintering furnace has problem

[Zubler USA]

Is that helpful to run the tray covered? I always leave it uncovered

Hi Desert Fox, It can be helpful to cover the tray. There are multiple factors that play into that decision. A simplified way to explain:
Slow sintering cycles - cover the tray
Wet zirconia - cover the tray.
Speed cycles with dry zirconia - no worries
Just always make sure to run your regeneration cycles regularly. (At least once a month)
BTW - sorry it took so long to reply. Haven't been on DLN for a while.